Python Mysql Docker Connection

Question

first of all I must say that I am totally new on Docker. I want to make an app that uses a Python script to connect to a mysql database and read a table showing the first rows. I am working on ubuntu 18.04

I have a dockerfile file with reference to the Python script, I have the Python script and I have the docker-compose (.yml) file.

The dockerfile is:

FROM python:latest

WORKDIR /app

COPY . /app
RUN pip install --trusted-host pypi.python.org -r requirements.txt

EXPOSE 80

CMD ["python", "reg.py"]

The Docker compose file is:

version: '3.3'

services:

  mysqldev:
    image: mysql:5.7
    volumes:
      - type: volume
        source: my-db
        target: /home/pakin/Documents/db-on-docker
    command: --secure-file-priv=/home/pakin/Documents/db-on-docker
    environment:
      MYSQL_ROOT_PASSWORD: 1234
      MYSQL_DATABASE: pruebas

    ports:
      - "3308:3306"
    restart: always

  reg-py:
    build: .
    depends_on:
      - mysqldev

# Names our volume
volumes:
  my-db:

And the Python script is:

import numpy as np
import pandas as pd
from sqlalchemy import create_engine
import pymysql

engine = create_engine('mysql+pymysql:/root:1234@mysqldev:3306/pruebas')

df = pd.read_sql_query('SELECT * FROM reg_db', engine)
df.head()

Using docker-compose up the app initiates but the Python script shows an error 2003, "Can't connect to MySQL server on 'localhost' ([Errno 99] Cannot assign requested address then the mysql container works fine but python simply does not connect to it.

I appreciate any help you can provide me!

amarynets · Accepted Answer · 2019-08-16 18:10:09Z

1

The easiest solution will be set IP to mysqldev as an env variable:

reg-py:
    build: .
    environment:
      - MY_SQL_IP:mysqldev
    depends_on:
      - mysqldev

and in your code:

db_ip = os.environ['MY_SQL_IP']
engine = create_engine(f'mysql+pymysql:/root:1234@{db_ip}:3306/pruebas')

UPD 1: - "3308:3306" is - "HOST:CONTAINER". So you should use port 3308 or create network

edited Aug 16, 2019 at 18:10

answered Aug 16, 2019 at 15:19

amarynets

1,82511 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Pakin Over a year ago

Thank you @amarynets i just tried your solution but still the same error. Do You think it has to do with ports or paths?

Nikhil VJ Over a year ago

note: the port mapping is for the outside world, not for the internal network which the python and mysql containers are in. so, from python, mysql port num is the original 3306 only.

Collectives™ on Stack Overflow

Python Mysql Docker Connection

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related